To say "don't eat something" in Engpsh, you can say "don't eat" followed by the name of the thing you don't want to eat. For example:

"Don't eat that cookie."
"Don't eat those chips."

You can also use the phrase "don't have" followed by the name of the thing you don't want to eat. For example:

"Don't have any more cake."
"Don't have any more soda."

If you want to be more formal, you can use the phrase "please refrain from eating" followed by the name of the thing you don't want to eat. For example:

"Please refrain from eating any more candy."
"Please refrain from eating any more ice cream."